Snap action type relay



Oct. 24, 1967 R. D. KEENAN 3,349,353

SNAP ACTION TYPE RELAY Filed Aug. 16, 1965 FIG.2A M

A FIG.4B '9 v FIGZB INVENTOR RALPH D. KEENAN United States Patent ()fihce 3,349,353 Patented Oct. 24, 1967 ABSTRACT OF THE DISCLOSURE A relay with a toggle spring, which after it has passed its toggle point upon energization of the relay electro magnet, coacts with the contact spring operating arm of the relay armature to cause the contact springs to be operated with a snap action. After the electromagnet has been de-energized and the toggle spring has passed the toggle point in the opposite direction, the toggle spring exerts pressure on the armature arm and the pressure holds the armature in its normal, unoperated position.

My invention relates in general to a snap action relay andmore specifically to a light current relay which has an extra bowed or toggle type tension spring which exerts a strong pressure against the armature of the relay when in normal position and which reduces such pressure as the armature is operated past the toggle point of the bowed spring.

Relays have been used in the past to operate one or two micro switches which have a snap or toggle action, but the number of switches operated is limited and I propose the use of such a bowed or toggle spring mounted in the relay in such a manner as to cause a snap action to the armature, and still permit as many sets of spring contacts to be mounted on the relay spring pile up as is presently possible.

A relay such as herein disclosed has many distinct advantages in use as a light current or alternating current relay where it is important to prevent chattering and where a critical amount of current is required for operation of the armature and a lesser amount of current will still hold the armature in operated position after its snap action.

The invention will be more fully understood from the following detailed description referring to the accompanying drawing in which:

FIG. 1 is a front view of a relay showing one embodiment of my invention.

FIG. 2 is a view taken from the top of FIG. 1.

FIG. 2A is a plan view of the back stop spring mounted adjacent the cantilever snap spring in the spring pile up.

FIG. 2B is a plan view of the cantilever spring shown in FIG. 1.

FIG. 3 is a front view of another embodiment of my invention showing a relay with a bowed or snap action spring acting on the armature.

FIG. 4 is a view taken from the top of FIG. 3.

FIG. 4A is a top view of the bracket shown in FIGS. 3 and 4 for supporting the bowed spring.

FIG. 4B is a side view of such bracket showing the bowed spring mounted thereon.

Referring now to the drawing, in FIGS. 1 and 2, I have shown a relay of the so called class B type to which a snap action spring has been applied. This relay includes the usual coil 2 with its pole piece 3 upon which is mounted the heel piece 4. Armature 5 is mounted on heel piece 4 by means of bracket 6. The heel piece is secured to the core 3 by screw 7 and has bent down projections 8 which act as the back stops for the free ends 9 and 10 of armature 5. The armature has the two arms 9 and 10 for operating sets of contact springs such as 11. In this instance for the purpose of clarity, I have shown only one set of circuit closing springs at 11 operated by arm 10 but it will be understood that several groups of such springs may be mounted under the plates 12 and 13 on each side of the heel piece for operation by the arms 9 and 10 of the armature. The springs shown at 11 are of the twin contact type customarily used in such relays.

At 14 I have shown a snap action spring of a cantilever type with a backing spring 15 mounted above the spring 14- and rigidly secured at the left ends under the plate 13. The elements 14 and 15 are shown clearly in FIGS. 2A and 2B. Spring 14 is bent downward at point 14:: of FIG. 2B and bowed upward again at point 14b. The edge is snapped tightly into the knife edge slot in the end of armature arm 9; The backing spring 15 when clamped under plate 13 extends outward along spring 14 almost to point 14a so that spring 14 acts as a cantilever or toggle normally tending to exert tension to hold the armature in retracted position by tending to press arm 9 downward as seen in FIG. 1. As the coil is energized and armature 5 attracted to core 3, the arm 9 moves upward until the springs 11 are operated at which time the spring 14 has been moved past its toggle point and its tension no longer tends to move arm 9 downward. In fact, a force is now applied by spring 14 upwardly against contact springs 11, thereby aiding the magnetic operating force of the armature. At this point, furthermore, only the tension of the contact springs 11 will have any restoring tension on arm 9. The tension of bowed spring 14 also tends to hold the armature 5 tightly against its pivot point so as to reduce wear at such point. Because of the above-mentioned aiding effect the relay according to the invention is able to handle greater contact spring loads. Moreover downward tension exerted by the armature springs of the pileup need not be relied upon, in the unoperated condition of the relay, to hold the armature in its normal position. Because of this, there is no corresponding increase in the current required to hold the relay in its operated condition. As previously stated, additional sets of springs may be mounted under plate 13 as well as under plate 12, and be operated by bushing 16.

Referring now to FIGS. 3, 4, 4A and 4B, I will de scribe the embodiment of my invention shown therein. In these figures, a similar class B type relay is shown having the same coil, core, armature, heel piece, and contact closing springs as has the relay of FIGS. 1 and 2 and like parts are given corresponding numbers. In this relay, instead of the cantilever spring 14 with its backing spring 15, I have provided a special bracket 17 having the two upturned ends 18 and 19 having knife edge slots on their inner surfaces as shown in FIGS. 4A and 4B. Mounted in the slots is a clock spring 20 which is bowed as shown with its ends snapped tightly into the knife edges and the center or lower parts of the bow lying directly above and pressing against the bushing 16 on armature arm 9 as seen in FIG. 3. The bracket 17 is mounted at the lower point in the spring pile up and held in place by plate 13. The bushing 21 of spring combination 11 lies against the upper surface of the center of spring 24). It will thus be seen that, in addition to the usual tension of the bushings of the spring combinations, the bowed spring 2i) exerts normally considerable tension against arm 9 of armature 5. As the coil is energized the armature 5 is attracted and presses the bushings 16 and 21 upward against the tension of spring 20 until the armature pushes spring 20 up beyond its center or toggle point. At this point, the armature snaps quickly to its advanced attracted position and has only the tension of the contact making springs to overcome. As in the other embodiment of FIGS. 1 and 2 the regular bushings of the contact making spring combinations need not have as much tension as is usually required because the force due to the downward tension of the bowed spring is suificient to hold the armature in its normal position when the relay is unoperated. Here too, because of this, no corresponding increase in the current is required to hold the relay in its operated condition. Also, there is less tendency of chattering of the armature on variations of DC. current or when the relay is operated by AC.

Having fully described the features and aspects of my invention, what I consider to be new and desire to have protected by Letters Patent will be pointed out in the appended claims.

What is claimed is:

1. A relay including an electromagnet, a heelpiece, a plurality of contact springs, an armature having an arm for operating said contact springs, said contact Springs and said heelpiece extending in a direction generally parallel to said operating arm, said armature being operable by said electrornagnet against the action of said springs, and toggle means including a spring of the cantilever type having a bowed portion on one end thereof with the other end being secured to said heelpiece, said spring extending in a direction generally parallel to said operating arm, said operating arm including at one end thereof, a knife-edged slot, said bowed end portion of said spring being fitted into said slot so that upon the energization of said electromagnet and subsequent to the passing of said toggle means beyond its toggle point, said toggle means coacts with said armature to cause said contact springs to be operated with a snap action, and that upon the deenergization of said electromagnet and subsequent to the passing of said toggle means beyond said toggle point in the opposite direction under the action of said contact springs, pressure is exerted on said arm by said spring to hold said armature in its normal, unoperated position.

2. A relay including an electromagnet, a heelpiece, a plurality of contact springs, an armature having an arm for operating said contact springs, said contact springs and said heelpiece extending in a direction generally parallel to said operating arm, said armature being operable by said electromagnet against the action of said springs, and toggle means including a bracket mounted on said heelpiece beneath said contact springs and extending in the direction of said operating arm, said bracket having a pair of upturned ends, each end having a knifeedged slot therein, and a flat bowed spring with two ends, each of the ends of said spring being fitted into a respective one of said knife-edged slots so that upon the energization of said electromagnet and subsequent to the passing of said toggle means beyond its toggle point, said toggle means coacts with said armature to cause said contact springs to be operated with a snap action, and that upon the deenergization of said electromagnet and subsequent to the passing of said toggle means beyond said toggle point in the opposite direction under the action of said contact springs, pressure is exerted on said arm by said spring to hold said armature in its normal, unoperated position.

References Cited UNITED STATES PATENTS 2,487,751 11/1949 Buckthal et a1. 335188 X 2,753,416 7/1956 McClain 335-188 2,456,112 12/1948 Dodd 335188 2,978,591 4/1961 Ringger 335188 X FOREIGN PATENTS 619,660 3/1949 Great Britain.

BERNARD A. GILHEANY, Primary Exarriiner.

R. N. ENVALL, Assistant Examiner. 

1. A RELAY INCLUDING AN ELECTROMAGNETIC, A HEELPIECE, A PLURALITY OF CONTACT SPRINGS, AN ARMATURE HAVING AN ARM FOR OPERATING SAID CONTACT SPRINGS, SAID CONTACT SPRINGS AND SAID HEELPIECE EXTENDING IN A DIRECTION GENERALLY PARALLEL TO SAID OPERATING ARM, SAID ARMATURE BEING OPERABLE BY SAID ELECTROMAGNET AGAINST THE ACTION OF SAID SPRINGS, AND TOGGLE MEANS INCLUDING A SPRING OF THE CANTILEVER TYPE HAVING A BOWED PORTION ON ONE END THEREOF WITH THE OTHER END BEING SECURED TO SAID HEELPIECE, SAID SPRING EXTENDING IN A DIRECTION GENERALLY PARALLEL TO SAID OPERATING ARM, SAID OPERATING ARM INCLUDING AT ONE END THEREOF, A KNIFE-EDGE SLOT, SAID BOWED END PORTION OF SAID SPRING BEING FITTED INTO SAID SLOT SO THAT UPON THE ENERGIZATION OF SAID ELECTROMAGNET AND SUBSEQUENT TO THE PASSING OF SAID TOGGLE MEANS BEYOND ITS TOGGLE POINT, SAID TOGGLE MEANS COACTS WITH SAID ARMATURE TO CAUSE SAID CONTACT SPRINGS TO BE OPERATED WITH A SNAP ACTION, AND THAT UPON THE DEENERGIZATION OF SAID ELECTROMAGNET AND SUBSEQUENT TO THE PASSING OF SAID TOGGLE MEANS BEYOND SAID TOGGLE POINT IN THE OPPOSITE DIRECTION UNDER THE ACTION OF SAID CONTACT SPRINGS, PRESSURE IS EXERTED ON SAID ARM BY SAID SPRING TO HOLD SAID ARMATURE IN ITS NORMAL, UNOPERATED POSITION. 